Bryonolic Acid, a Triterpenoid, Protect Against N-methyl-d-Aspartate-Induced Neurotoxicity in PC12 Cells

Luteolin-7-O-β-d-glucuronide Ameliorates Cerebral Ischemic Injury: Involvement of RIP3/MLKL Signaling Pathway

Luteolin-7-O-β-d-glucuronide (LGU) is a major active flavonoid glycoside compound that is extracted from Ixeris sonchifolia (Bge.) Hance, and it is a Chinese medicinal herb mainly used for the treatment of coronary heart disease, angina pectoris, cerebral infarction, etc. In the present study, the neuroprotective effect of LGU was investigated in an oxygen glucose deprivation (OGD) model and a middle cerebral artery occlusion (MCAO) rat model. In vitro, LGU was found to effectively improve the OGD-induced decrease in neuronal viability and increase in neuronal death by a 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and a lactate dehydrogenase (LDH) leakage rate assay, respectively. LGU was also found to inhibit OGD-induced intracellular Ca2+ overload, adenosine triphosphate (ATP) depletion, and mitochondrial membrane potential (MMP) decrease. By Western blotting analysis, LGU significantly inhibited the OGD-induced increase in expressions of receptor-interacting serine/threonine-protein kinase 3 (RIP3) and mixed lineage kinase domain-like protein (MLKL). Moreover, molecular docking analysis showed that LGU might bind to RIP3 more stably and firmly than the RIP3 inhibitor GSK872. Immunofluorescence combined with confocal laser analyses disclosed that LGU inhibited the aggregation of MLKL to the nucleus. Our results suggest that LGU ameliorates OGD-induced rat primary cortical neuronal injury via the regulation of the RIP3/MLKL signaling pathway in vitro. In vivo, LGU was proven, for the first time, to protect the cerebral ischemia in a rat middle cerebral artery occlusion (MCAO) model, as shown by improved neurological deficit scores, infarction volume rate, and brain water content rate. The present study provides new insights into the therapeutic potential of LGU in cerebral ischemia.

The health benefits of santol fruits and bioactive products isolated from Sandoricum koetjape Merr.: A scoping review

The santol tree (Sandoricum koetjape Merr.) is largely distributed in Southeast Asia. It produces useful timber and edible fruits, consumed fresh, and transformed. It has a wide range of traditional medicinal uses for the treatment of inflammatory disorders and digestive troubles. Numerous bioactive natural products have been isolated from the roots, leaves, stems, and fruits of S. koetjape, including flavonoids, limonoids, and terpenoids. The seeds are considered toxic and contain insecticidal limonoids. The present review provides a survey of the natural products isolated from different parts of the plant and discusses their pharmacological properties. Information on S. koetjape was collected through databases and analyzed, leading to the identification of about 30 natural products of interest. Bioactive compounds include limonoids, such as sandoripins A-B, sanjecumins A-B, and sandrapins A-E, and flavonoids with antioxidant, antibacterial, and insecticidal properties such as sandoricin and sandoripin derivatives. The santol plant contains various anti-inflammatory triterpenes, such as sentulic acid and koetjapic acid (KA). KA is the main product found in santol and a few other plants. This tetracyclic triterpenoid is endowed with anti-inflammatory and anticancer properties, with marked antimetastatic and antiangiogenic effects. Its potential molecular targets are discussed, notably the kinase mammalian target of rapamycin (mTOR) and other proteins (cyclooxygenase 2, DNA polymerase-β). The water-soluble derivative potassium koetjapate (KK) affords an orally bioavailable derivative, with superior antiangiogenic properties compared to KA. The health benefits associated with the consumption of santol fruits shall be further considered, and the design of hemi-synthetic analogs of KA encouraged. PRACTICAL APPLICATIONS: The fruits of the santol tree are largely consumed in Asia and different parts of the plant (Sandoricum koetjape Merr.) are used in traditional medicine. Diverse bioactive terpenoids have been isolated from the plant. Their pharmacological properties are reviewed here, with a focus on the triterpene koetjapic acid which displays marked anti-inflammatory and anticancer properties. Several other bioactive natural products, including limonoids and flavonoids, are evoked as well, to shed light on the many active compounds found in the fruits and the whole plant. For a healthy life, the use of the plant in phytomedicine and the consumption of the santol fruit should be encouraged.

Dynorphin A (1-8) inhibits oxidative stress and apoptosis in MCAO rats, affording neuroprotection through NMDA receptor and κ-opioid receptor channels

The contents of Dynorphin A(1-8) decreased gradually in ischemic cortices in rats and an intracerebroventricular administration of synthetic Dynorphin A(1-8) reduced the volume of cerebral infarction in our previous research. However, the specific protective mechanism is unclear and Dynorphin A(1-8) is unlikely to cross the blood-brain barrier (BBB) by noninvasive oral or intravenous administration as a macromolecule neuropeptide. In this study, intranasal administration was used to middle cerebral artery occlusion(MCAO) rats to assessed the therapeutic effects of Dynorphin A(1-8) by evaluating behavior, volume of cerebral infarct, cerebral edema ratio, histological observation. Then apoptosis neuron rate was detected by TUNEL staining. Immunohistochemical staining was carried out to explore the alteration of Bcl-2, Bax and Caspase-3. Finally, κ-opioid receptor antagonist and N-methyl-d-aspartate(NMDA) receptor antagonist were used to explore its possible mechanism. We found that MCAO rats under intranasal administration of Dynorphin A(1-8) showed better behavioral improvement, higher extent of Bcl-2, activity of SOD along with much lower level of infarction volume, brain water content, number of cell apoptosis, extent of Bax and Caspase-3, and concentration of MDA compared with those in MCAO model group and intravenous Dynorphin A(1-8) group. Administration of nor-BNI or MK-801 reversed these neuroprotective effects of intranasal Dynorphin A(1-8). In summary, Dynorphin A(1-8), with advantages of intranasal administration, could be effectively delivered to central nervous system(CNS). Dynorphin A(1-8) inhibited oxidative stress and apoptosis against cerebral ischemia/reperfusion injury, affording neuroprotection through NMDA receptor and κ-opioid receptor channels.

TCMIP v2.0 Powers the Identification of Chemical Constituents Available in Xinglou Chengqi Decoction and the Exploration of Pharmacological Mechanisms Acting on Stroke Complicated With Tanre Fushi Syndrome

Xinglou Chengqi (XLCQ) decoction, composed of three botanical drugs and one inorganic drug, is used in clinics during the treatment of acute stroke complicated with Tanre Fushi (TRFS) syndrome in China. However, its active ingredients and the molecular mechanism have not been clarified. So, we aimed to preliminarily characterize its chemical constituents and investigate its pharmacological mechanisms using an integrative pharmacology strategy, including component analysis, network prediction, and experimental verification. We employed UPLC-QTOF-MS/MS to describe the chemical profile of XLCQ, Integrative Pharmacology-based Network Computational Research Platform of Traditional Chinese Medicine (TCMIP v2.0, http://www.tcmip.cn/), to assist in identifying the chemical components and predict the putative molecular mechanism against acute stroke complicated with TRFS, and LPS-stimulated BV-2 cells to verify the anti-neuroinflammatory effects of luteolin, apigenin, and chrysoeriol. Altogether, 197 chemical compounds were identified or tentatively characterized in the water extraction of XLCQ, 22 of them were selected as the key active constituents that may improve the pathological state by regulating 27 corresponding targets that are mainly involved in inflammation/immune-related pathways, and furthermore, luteolin, apigenin, and chrysoeriol exhibited good anti-neuroinflammatory effects from both protein and mRNA levels. In summary, it is the first time to employ an integrative pharmacology strategy to delineate 22 constituents that may improve the pathological state of stroke with TRFS by regulating 27 corresponding targets, which may offer a highly efficient way to mine the scientific connotation of traditional Chinese medicine prescriptions. This study might be a supplement for the deficiency of the basic research of XLCQ.

Enhanced Production of Bryonolic Acid in Trichosanthes cucumerina L. (Thai Cultivar) Cell Cultures by Elicitors and Their Biological Activities

Bryonolic acid is a triterpenoid compound found in cucurbitaceous roots. Due to its biological activities, this compound gets more attention to improve production. Herein, we carried out efficient ways with high bryonolic acid productions from Trichosanthes cucumerina L., a Thai medicinal plant utilizing plant cell cultures. The results showed that calli (24.65 ± 1.97 mg/g dry weight) and cell suspensions (15.69 ± 0.78 mg/g dry weight) exhibited the highest bryonolic acid productions compared with natural roots (approximately 2 mg/g dry weight). In the presence of three elicitors (methyl jasmonate, yeast extract, and chitosan), cell suspensions treated with 1 mg/mL of chitosan for eight days led to higher bryonolic acid contents (23.56 ± 1.68 mg/g dry weight). Interestingly, cell culture and root extracts with high bryonolic acid contents resulted in significantly higher percent cell viabilities than those observed under control (1% v/v DMSO) treatment in Saos-2 and MCF-7 cells. The present study indicated that T. cucumerina L. cell cultures are alternative and efficient to produce the biologically important secondary metabolite.

Paeoniflorin attenuates atRAL-induced oxidative stress, mitochondrial dysfunction and endoplasmic reticulum stress in retinal pigment epithelial cells via triggering Ca2+/CaMKII-dependent activation of AMPK

Abnormal accumulation of the free-form all-trans-retinal (atRAL), a major intermediate of human visual cycle, is considered to be a key cause of retinal pigment epithelial (RPE) dysfunction in the pathogenesis of retinal degenerative diseases such as age-related macular degeneration (AMD). Paeoniflorin (PF), a monoterpene glucoside isolated from Paeonia lactiflora Pall., has been used in clinical treatment of retinal degenerative diseases in China for several years; however, the underlying mechanism remains unclear. The aim of this study is to investigate the protective effect of PF against atRAL toxicity in human ARPE-19 cells and its molecular mechanism. The results of our study showed that the pre-treatment of PF dose-dependently attenuated atRAL-induced cell injury by the reduction of Nox1/ROS-associated oxidative stress, mitochondrial dysfunction and GRP78-PERK-eIF2α-ATF4-CHOP-regulated endoplasmic reticulum (ER) stress in ARPE-19 cells. Additionally, our data showed that PF mainly exerted its activity via triggering calcium-calmodulin dependent protein kinase II (CaMKII)-mediated activation of AMP-activated protein kinase (AMPK). AMPK inhibition significantly reversed the protective effect of PF against atRAL toxicity in ARPE-19 cells. Overall, our findings provided the novel mechanism of PF protecting human RPE cells, which may prevent the progression of retinal degenerative diseases.

Bryonolic Acid Blocks Cancer Cell Clonogenicity and Invasiveness through the Inhibition of Fatty Acid: Cholesteryl Ester Formation

Bryonolic acid (BrA) is a pentacyclic triterpene present in several plants used in African traditional medicine such as Anisophyllea dichostyla R. Br. Here we investigated the in vitro anticancer properties of BrA. We report that BrA inhibits acyl-coA: cholesterol acyl transferase (ACAT) activity in rat liver microsomes in a concentration-dependent manner, blocking the biosynthesis of the cholesterol fatty acid ester tumour promoter. We next demonstrated that BrA inhibits ACAT in intact cancer cells with an IC₅₀ of 12.6 ± 2.4 µM. BrA inhibited both clonogenicity and invasiveness of several cancer cell lines, establishing that BrA displays specific anticancer properties. BrA appears to be more potent than the other pentacyclic triterpenes, betulinic acid and ursolic acid studied under similar conditions. The inhibitory effect of BrA was reversed by exogenous addition of cholesteryl oleate, showing that ACAT inhibition is responsible for the anticancer effect of BrA. This report reveals new anticancer properties for BrA.

Paeoniflorin exerts neuroprotective effects against glutamate‑induced PC12 cellular cytotoxicity by inhibiting apoptosis

Paeoniflorin (PF) is an active ingredient of Radix Paeoniae, which is known to exert neuroprotective effects. However, the mechanims behind the neuroprotective effects of PF are not yet fully understood. The apoptosis of neurons plays an important role in the cerebral ischemia-induced cascade response. This study aimed to investigate neuroprotective effects of PF against glutamate‑induced PC12 cellular cytotoxicity and to determine whether these effects are mediated via the inhibition of apoptosis in vitro and the activity of mitochondrial apoptosis-associated proteins in PC12 cells. Exposure of the PC12 cells to glutamate induced cell morphological changes, significantly decreased cell viability and induced apoptosis, with similar results being observed from the Hoechst 33342 staining and Annexin V/PI staining experiments. Glutamate also increased the lactate dehydrogenase release by the PC12 cells. However, treatment with PF prevented these effects. Furthermore, PF inhibited Bax and Bad expression and increased Bcl-2 and Bcl-xL expression; it also decreased the levels of downstream protein (caspase-3 and caspase-9). Collectively, our results indicate that PF protects PC12 cells against glutamate-induced neurotoxicity possibly through the inhibition of the expression of mitochondrial apoptosis-associated proteins.

The Role of TRPC6 in the Neuroprotection of Calycosin Against Cerebral Ischemic Injury

Our previous studies have provided evidences that calycosin can protect the brain from ischemia/reperfusion injury, but its mechanisms is not fully understand. Transient receptor potential canonical 6 (TRPC6) has a critical role in promoting neuronal survival against cerebral ischemic injury. The aim of the present study is to test whether calycosin protects against cerebral ischemic injury through TRPC6-CREB pathway. In vivo, rats were subjected to transient middle cerebral artery occlusion (MCAO) for 2 h and then treated with different doses of calycosin at the onset of reperfusion. In vitro, primary cultured neurons were treated by calycosin, then exposed to 2 h oxygen glucose deprivation (OGD) followed by 24 h reoxygenation. Our results showed that treatment with calycosin protected against ischemia-induced damages by increasing TRPC6 and P-CREB expression and inhibiting calpain activation. The neuroprotection effect of calycosin was diminished by inhibition or knockdown of TRPC6 and CREB. These findings indicated that the potential neuroprotection mechanism of calycosin was involved with TRPC6-CREB pathway.